3 Arc-Second Coastal Relief Model Development

Currently, the soundings used to create the East Coast grids are
referenced to two vertical datums and various horizontal datums. The
vertical datums are mean low water (89% of the surveys) and mean lower
low water (11%) of the surveys). The primary horizontal datums used were
the NAD27 ellipsoid for soundings collected up until 1987-88, and the
NAD83 ellipsoid for soundings collected since then. Despite their lack
of uniformity, the different horizontal and vertical datums do not
significantly alter the accuracy of the East Coast grids. This is
because there is little difference in elevation between mean low water
and mean lower low water in the gridding region, and the horizontal
differences between the ellipsoids is less than the horizontal
resolution of the cells within the grids (i.e.,<90m).

U.S. Geological Survey mapped from the La Jolla Canyon south to the US-Mexico border using a Kongsberg Simrad multibeam echosounder system (MBES) (March - April 1998). Data and metadata available at http://pubs.usgs.gov/of/2004/1221/.

Woods Hole Oceanographic Institution and SCRIPPS Institution of Oceanography mapped the majority of the La Jolla Fan Valley including the sea floor to the north and south of the valley using a Seabeam 2100 MBES. Data available at http://www.ngdc.noaa.gov/mgg/bathymetry/multibeam.html. Survey ID, AT07L09, Chief Scientists, Barrie Walden and Joseph Coburn (April 2002).

California State University, Monterey Bay, mapped Scripps Canyon and the head of La Jolla Canyon using a Reson 8101 MBES (October 2001). Data and metadata available at http://seafloor.csumb.edu/SFMLwebDATA.htm. This work was funded by the California Department of Fish and Game

California Coastal Conservancy, San Diego Association of Governments (SANDAG), California Department of Fish and Game, and Fugro Pelagos mapped the nearshore region out to about 35-40 m.

The sea floor within this image that has not been mapped with MBES is filled in with interpreted bathymetry gridded from single-beam data available at http://www.ngdc.noaa.gov/mgg/bathymetry/hydro.html. Depths are in meters below sea level, which is referenced to Mean Lower Low Water.